66855870 has 48 divisors (see below), whose sum is σ = 182978640. Its totient is φ = 16889472.

The previous prime is 66855827. The next prime is 66855881. The reversal of 66855870 is 7855866.

66855870 is a `hidden beast` number, since 6 + 68 + 5 + 587 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17839 + ... + 21258.

It is an arithmetic number, because the mean of its divisors is an integer number (3812055).

Almost surely, 2^66855870 is an apocalyptic number.

66855870 is an abundant number, since it is smaller than the sum of its proper divisors (116122770).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66855870 is a wasteful number, since it uses less digits than its factorization.

66855870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39129 (or 39126 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The square root of 66855870 is about 8176.5438909114. The cubic root of 66855870 is about 405.8633616897.

The spelling of 66855870 in words is "sixty-six million, eight hundred fifty-five thousand, eight hundred seventy".